Three-dimensional band diagram in lateral polarity junction III-nitride heterostructures

Wei Guo,Moheb Sheikhi,Houqiang Xu,Somak Mitra,Xiaohang Li,Iman S Roqan,Jichun Ye,Kangkai Tian,Zi-Hui Zhang,Haiding Sun,Haibo Jiang,Jie’An Jiang

doi:10.1364/optica.6.001058

Abstract

The 2D band diagram comprising out-of-plane potentials has been ubiquitously utilized for III-nitride heterostructures. Here, we propose the 3D band diagram based on unambiguous evidences in luminescence and carrier dynamics for lateral polarity junction quantum wells: although electrons and holes are separated out-of-plane in quantum wells by polarization, different band diagram heights lead to secondary carrier injection in-plane, causing electrons to transport from the III- to N-polar domains to recombine with holes therein with large wavefunction overlap. We also show that utilization of the 3D band diagram can be extended to single-polarity structures to analyze carrier transport and dynamics, providing new dimensions for accurate optical device design.

Highlights

III-nitride semiconductors have enabled numerous essential optical applications including lighting and display
To further understand sub-microscale optical behavior of the lateral polarity junction (LPJ) multiple QWs (MQWs), CL spectra were recorded at RT
The N-polar domains show much stronger MQW emission than the III-polar domains, which is consistent with the PL (Fig. 1)

Summary

INTRODUCTION

III-nitride semiconductors have enabled numerous essential optical applications including lighting and display. The design and optimization of most III-nitride devices hinge on device band diagrams to accurately compute and analyze carrier transport and dynamics processes including recombination. We show that by reducing the LPJ to micrometer size, emission intensity of the LPJ multiple QWs (MQWs) can be dramatically improved compared to the uniform III-polar MQWs [8] It is unclear exactly how the LPJ enhances radiative recombination. Different from the conventional 2D band diagram model, we propose the 3D band diagram model to explain carrier transport and dynamics of the LPJ MQWs. we point out that the applications of the 3D band diagram can be further extended to single-polarity structures with in-plane potential variation and out-of-plane band bending. The proposal of the 3D band diagram could inspire new perspectives in the design and analysis of III-nitride optical devices regardless of the polarity

EXPERIMENT

RESULTS AND DISCUSSION

CONCLUSION